Putting strokes represent approximately 42% of the average golf round. During the putting stroke, the blade of the putter should be drawn directly back along the intended line of putt and then thrust forward, not deviating from the line, and the blade face should remain perpendicular to said line. Moreover, the putter blade should accelerate through the ball so that a true rolling action is imparted. This is important since a vertical spinning action on the ball will tend to keep it on the putting line.
If the face of the putter is one degree off from being perfectly perpendicular to the putting line at contact with the ball, there will be a deviation of 1.2" at five feet and a missed putt may result. Of course, the deviation increases or decreases as the length of the putt increases or decreases, respectively.
What is needed, then, is a putting aid that tells a golfer whether or not the stroke deviated from the intended line of putt and that further provides an indication as to the degree and direction of deviation. An ideal device would even indicate whether or not the putting stroke included a proper follow through.
The prior art, at the time the present invention was made and when considered as a whole in accordance with the requirements of law, neither taught nor suggested to those of ordinary skill in the putting aid industry how the art could be significantly advanced.